1. Technical Field of the Invention
The present invention relates generally to an improved structure of a liquid drop emitter, and more particularly to a liquid drop emitter designed to emit a plurality of minute drops of liquid and deposit them on a substrate in a dense array of dots to produce a DNA chip, for example.
2. Background Art
In recent years, rapid progress has been made in analyzing gene structure. Various kinds of gene structures as well as human gene structures have been found. Such gene analysis usually uses a DNA chip on which more than a few thousand types of DNA fragments are deposited and immobilized in an array of minute spots.
Such deposition on the DNA chip is typically achieved using a quill mechanism, a pin-ring mechanism, or a spring pin mechanism. In either case, improvement of productivity of DNA chips, i.e., increasing of speed of production thereof and increasing of accuracy of encoding DNA information are sought. Such increasing of accuracy requires uniformity of quantity and concentration of drops of liquid containing DNA fragments.
Typical DNA chip production uses a liquid drop emitter which includes a plurality of micropipettes each consisting of a liquid inlet, a liquid sump, a compression chamber, an outlet nozzle. The micropipettes are arranged in parallel to each other. A liquid inlet and a discharge nozzle are arranged in one line toward the base body. The actuator that compresses the liquid inside of the compression chambers is located outside the compression chambers in such a liquid drop emitter. For example, a piezoelectric/electrostrictive element is used as this actuator.
In order to increase the speed and efficiency of production of DNA chips using the above type of liquid drop emitter, it is necessary to decrease the size of the micropipettes and arrange them close to each other to provide as many outlet nozzles as possible per unit area. In other words, it is the plan that DNA chip manufacture be sped up by closely arranging the discharge nozzles so that many drops may be formed on slide glass.